Through point A of the circle, the diameter AC and two chords AB and AD are drawn so that the chord AB

Through point A of the circle, the diameter AC and two chords AB and AD are drawn so that the chord AB is equal to the radius of the circle, point D divides the semicircle AC into two equal arcs. Find the corners of a quadrilateral ABCD if points B and D are on opposite sides of the diameter AC.

OAB – equilateral ⇒ OBA = OAB = AOB = 60 °, AB = 60 °.
OAD – equilateral ⇒ OAD = ODA = AOD = 60 °, AD = 60 °.
BAD = OAB + OAD;
BAD = 60 ° + 60 °;
BAD = 120 °;
OBC – isosceles;
BОС = 180 ° – 60 °;
BОС = 120 °;
OCB = OBC = (180 ° – 120 °) / 2;
OCB = OBC = 30 °;
OCD – isosceles;
СОD = 180 ° – 60 °;
COD = 120 °;
ОDС = ОDС = (180 ° – 120 °) / 2;
ОDС = ОDC = 30 °;
CBA = CBO + ABO = 30 ° + 60 °;
CBA = 90 °;
CDA = CDO + ADO = 30 ° + 60 °;
CDA = 90 °;
ВСD = ВСО + DCО = 30 ° + 30 °;
ВСD = 60 °;